The present invention relates principally to apparatus delivering the liquid phase of a cryogenic fluid, which is stored under pressure in a storage tank, to a point open to free air at which it is to be used.
Cryogenic fluids, and in particular inert gases such as argon and nitrogen, are widely used at the present time in various technical fields; for example, in metallurgy for inertizing certain installations or pieces of apparatus or to protect molten metals by means of layers of liquid; in mechanics in the production of certain hydraulic or pneumatic mechanisms; in chemistry for cooling or solidifying certain substances, and so on. In these diverse applications the fluid has to be supplied in free air, i.e., at atmospheric pressure. However, supplying it under these conditions creates considerable problems, due to the severe turbulence which exists in the liquid phase. In cases where molten metals are being protected, this turbulence prevents a homogeneous protective layer from being obtained. When a container is being filled, particularly one of small dimensions, it causes losses, and it prevents an accurately metered quantity of the cryogenic fluid from ever being transferred.
Hitherto, no satisfactory solution has been found to the problem of supplying a cryogenic fluid in quantities capable of precise measurement under conditions which allow a smooth flow.